<style>
html, body {
    height: 100%;
    margin: 0;
    padding: 0;
}

body {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    font-family: "Microsoft YaHei";
    font-size: 12px;
    color: #666;
    line-height: 22px;
}

/* 内容区域 - 自动伸缩 */
.content {
    flex: 1 0 auto;
    width: 100%;
}

/* 页脚 - 固定高度 */
.footer {
    flex-shrink: 0;
    text-align: center;
}

.btn_box {height:28px; margin:2px 2px; float:left;}
.btn3_mouseout {width:128px; height:28px; background:url(../images/btn.gif) no-repeat; border:0px; color:#666; margin-top:3px;background-size: 100% 100%;}
#pc .btn3_mouseout {width:auto; height:auto; background:url(../images/btn.gif) no-repeat; border:0px; color:#666; margin-top:3px;background-size: 100% 100%;padding: 5px 10px;}
.btn5_mouseout {width:auto; height:auto; background:url(../images/btn.gif) no-repeat; border:0px; color:#00f; margin-top:3px;background-size: 100% 100%;padding: 5px 10px;}
.btn3_mouseover {width:128px; height:28px; background:url(../images/btn_over.gif) no-repeat; border:0px; color:#fff; margin-top:3px;}
.btn3_mouseoverpc {font-size: 1.2rem;font-weight:500; background:url(../images/btn_over.gif) no-repeat; border:0px; color:#fff; margin-top:3px;background-size: 100% 100%;padding: 5px 10px;}
.btn3_mousedown {font-size: 1.2rem;font-weight:500; background:url(../images/btn_over.gif) no-repeat; border:0px; color:#fff; margin-top:3px;background-size: 100% 100%;padding: 5px 10px;}
.btn3_mouseup {font-size: 1.2rem;font-weight:500; background:url(../images/btn_over.gif) no-repeat; border:0px; color:#fff; margin-top:3px;background-size: 100% 100%;padding: 5px 10px;}
.btn5_mouseover {width:128px; height:28px; background:url(../images/btn_over.gif) no-repeat; border:0px; color:#fff; margin-top:3px;}
.btn5_mouseoverpc {font-size: 1.5rem;font-weight: bold; background:url(../images/btn_over.gif) no-repeat; border:0px; color:#fff; margin-top:3px;background-size: 100% 100%;padding: 5px 10px;}
.btn5_mousedown {font-size: 1.5rem;font-weight: bold; background:url(../images/btn_over.gif) no-repeat; border:0px; color:#fff; margin-top:3px;background-size: 100% 100%;padding: 5px 10px;}
.btn5_mouseup {font-size: 1.5rem;font-weight: bold; background:url(../images/btn_over.gif) no-repeat; border:0px; color:#fff; margin-top:3px;background-size: 100% 100%;padding: 5px 10px;}

</style>